Electrical switching device



Aug. 9, 1955 E. F. MOCLAIN 2,715,210

ELECTRICAL SWITCHING DEVICE Filed Sept. 18, 1945 2 Sheets-Sheet l K N N LIL-11E gvwem/bcw EDWARD F. MCCLAIN EWQML LW Aug. 9, 1955 E. F. MQCLAIN 2,715,210

ELECTRICAL SWITCHING DEVICE 2 Sheets-Sheet 2 Filed Sept. 18, 1945 QMW EDWARD F. MC CLAlN m LULW United States Patent i This invention relates to electrical switching devices, and more particularly to a selector switch for switching high frequency energy in a waveguide to a selected one of several adjacent wave guides.

In employing electrical apparatus it is often desirable to switch electrical power from one terminal to one of several adjacent terminals. Where the electrical power is in the form of low frequency energy, it is usually feasible to employ contact type switches; however, where the electrical power is in the form of very high frequency energy requiring the use of specially designed transmission lines for efficient transmission of the power, it is not practical to employ contact type switching devices because of the high losses which would be involved. For this reason where the radio frequency energy is being transmitted by waveguides, complicated and often inefiicient switching mechanisms have been devised whereby the energy in a section of waveguide may be coupled to a selected one of a number of adjacent waveguides.

An object of the present invention is to provide an efiicient and effective selector switch for switching high frequency energy in a waveguide into a selected one of several adjacent waveguides.

In accordance with one embodiment of this invention, as applied to the switching of radio frequency energy in a waveguide to a selected one of several adjacent waveguides, a short section of waveguide is pivotally mounted at the end of the first waveguide and is pivotable to bring its outer end into alignment with any one of the ends of several waveguides which are radially disposed with respect to the pivot axis. Theouter end of the pivoted waveguide is fitted with a choke coupling which moves along the base of a curved flange into which the branch guides are soldered. A half wave trap is incorporated in the construction of the pivot to maintain low leakage.

Other objects and advantages of the present invention will be apparent from the following detailed description taken in conjunction with the drawings, wherein:

Fig. 1 is a plan view, partly in section, of an electrical switching device in accordance with one embodiment of this invention;

Fig. 2 is a side elevation, partly in section, of ,the structure shown in Fig. 1; and

Fig. 3 is an exploded perspective view of the structure shown in Figs. 1 and 2, having associated therewith three radially disposed waveguides.

Referring now to the drawings and particularly to Figs. 1 and 2 thereof, an end portion of a conventional waveguide 5 is there shown fragmentarily, the waveguide having a substantially rectangular cross section. A circular flange 6 is transversely mounted at the right end of the waveguide and is fixed to a circular radio frequency choke 7 of substantially conventional design. The choke 7 is provided with a deep annular slot (not shown) in, the face adjacent the flange 6 forming a wave trap to prevent radio frequency energy from escaping from the. junction in a direction perpendicular to the axis of the waveguide, as is well known in the art. Connected to the right side Z ,7 i 5 ,Z Patented Aug. 9, 1955 ice of the choke 7 and aligned with the waveguide 5 is a short section of waveguide 8, of similar dimensions to the waveguide 5, to the right end of which on either sidewall thereof, as shown in Fig. l, is fixed an arcuate block 9 the concave curved portion of which extends outward from the side wall to which it is attached and forward from the right end thereof. A circular disc It) is mounted at the base of the blocks 9, as shown in Fig. 3, and is so located with respect thereto that the periphery of the disc 10 is substantially aligned with the periphery of the blocks 9. The end of the waveguide 8 adjacent the blocks 9 and the interior surfaces of the blocks 9 are curved to form a cylindrical surface of revolution concentric with the axis of the disc 10, as may be seen in Fig. 3.

Pivotally supported on the disc 10, on a vertical axis perpendicular to the longitudinal axis of the waveguide S, in an annular bearing 12 suitably mounted therein, as shown in Fig. 3 is one end of a third section of waveguide 13, a stub shaft 14 fixed to the base of the waveguide 13 being rotatably supported by the bearing 12 and serving as a pivot mount for the lower side of the waveguide 13. A second disc 15, sirnilar to the disc 10, is mounted on the upper side of the blocks 9, as viewed in Fig. 2, and secured thereto. This disc is suitably apertured to receive an annular bearing 16 which rotatably supports a second stub shaft 17 associated with the upper side of the waveguide 13 and rotatable about an axis coaxial with the axis of rotation of the shaft 14. As may be seen in Fig. 1, the end of the waveguide 13 pivotally supported on the shafts 14 and 17 is so located thereby with respect to the adjacent end of the short section of waveguide 8 that it is aligned substantially therewith, this end of the waveguide 13 being curved to form a part of a cylindrical surface of revolution concentric with its axis of rotation and having a radius of curvature slightly less than the radius of curvature of the adjacent end of the waveguide 8. Half-round blocks 20 are mounted on either side of the waveguide 13 and have their outer surfaces convex curved, the radius of curvature being the same as the radius of curvature of the end of the waveguide 13. Thus the end of the waveguide 13, supported on the stub shafts 14 and 17 fits closely within the blocks 9 and adjacent the end of the waveguide S and yet is pivotable with respect thereto over a substantial arc.

In order to prevent loss of electrical energy in passing from the waveguide 8 to the waveguide 13, or vice-versa, and particularly when the waveguide 13 is pivoted with respect to the waveguide 8 so that its end is not aligned therewith, a radio frequency choke of novel design is incorporated in this pivot assembly. As may be seen in Figs. 1 and 3, rectangular plates 21 are mounted on the outer edges of the blocks 9, and are provided with a vertically extending slot 22 as viewed in Fig. 3. By extending the blocks 9, the slots 22 may be integrally formed in the forward opposed portions thereof, thus avoiding the necessity of employing the slotted plates 21. The slots 22 are made to have a depth equivalent to a quarter Wavelength, or an odd multiple thereof, of the wavelength of the radio frequency energy to be passed and are spaced from the edge of the sidewalls of the waveguide 8 a similar distance. They thus serve as a half wave radio frequency choke and prevent the escape of electrical energy from the pivot assembly. By filling the slots with a dielectric material 23, such as polystyrene, the required physical depth of the slots may be reduced since the higher dielectric constant of the polystyrene, as compared with air, provides an electrical path of equivalent length with less physical length.

The outer end of the waveguide 13 is provided with a circular radio frequency choke 24 of conventional design having an annular slot 25 substantially a quarter wavelength deep formed in the outer face thereof. This choke 24 is similar to the choke 7 heretofore described. Mounted adjacent the outer end of the choke 24 is a curved plate 26, the radius of curvature of the plate 26 being substantially equivalent to the distance of separation of the plate 26 from the axis of rotation of the waveguide 13. For purposes of illustration, three waveguide channels 27, 28 and 29 are shown mounted on the rear side of the plate 26 and radially disposed with respect to the axis of rotation of the waveguide 13. It will be understood that more or fewer branch channels may be used than the three illustrated without departing from the present invention. Where a larger number of channels are used it is desirable to employ a relatively longer section of waveguide 13 so that the maximum angle to which the waveguide 13 is misaligned with the waveguide 8 may be held to a minimum.

While it is desirable that the outer end of the waveguide 13, that is, the end provided with the choke 24, be located as closely as feasible to the curved surface of the plate 26 and so located that in its arc of movement, it will traverse the surface of the plate 26 and be successively aligned with the waveguide channels 27, 28 or 29, because of the construction of this device, considerable latitude .in spacing is permissible. In practice, it has been found that if the separation between the end of the waveguide 13 and the face of the plate 26 does not exceed one-tenth of a wavelength at the frequency of transmission, the losses which will be incurred are not objectionable.

' It will be readily apparent that any suitable method of pivoting the waveguide 13 may be employed. For purposes of illustration, a gear 30 is shown provided with a hub 31 which may be fitted to one of the stub shafts 14 or 17 and keyed thereto. It will be understood that gear 30 may be driven by any suitable means.

Where herein the various parts of this invention have been referred to as being in an upper or lower or right or left position, it will be understood that this is done solely for the purposes of description and that the references relate only to the relative positions of the. parts as shown in the accompanying drawings.

While but one em odiment of this invention has been shown and described, it will be understood that many changes and modifications may be made therein without departing from the spirit or scope of the present invention.

The invention shown and described herein may be manufactured or used by or for the Government of .the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

What is claimed is:

1. An electrical switching device for selectively coupling energy in a first hollow rectangular dielectric-filled waveguide to one of several adjacent hollow rectangular dielectric-filled waveguides including a radio frequency choke mounted on an end of said first waveguide and comprising a block mounted on each side wall of said first waveguide adjacent an end thereof, said blocks having opposed curved surfaces on their inner faces lying in a common cylindrical surface of revolution, said blocks having slots formed in the opposing faces thereof and extending parallel to the adjacent edges of the supporting side walls, said slots having a depth substantially electrically equivalent to a quarter wavelength of the wavelength of the electrical energy to be coupled, a pivotable hollow rectangular dielectric-filled wave guide pivotally mounted at one end on the axis of said cylindrical surface of revolution, a circular radio frequency choke mounted at the opposite end of said pivotable waveguide from that on which it is pivotally supported, and a plurality of radially disposed hollow rectangular dielectricfilled waveguides located adjacent said opposite end of said pivotable waveguide so as to be successively aligned with the end thereof as said waveguide is pivoted.

2. In a device for coupling radio frequency energy selected one of several adjacent hollow dielectric-filled waveguides, a second hollow dielectric-filled waveguide pivotally mounted at one end thereof for rotation in a plane containing the longitudinal axis of said first waveguide adjacent an end of said first waveguide, the other end of said pivotally mounted waveguide section being successively alignable with the end of each of the several waveguides to which energy is to be selectively coupled, a radio frequency choke mounted on said other end of said pivotable waveguide section, and a radio frequency choke associated with the junction of said pivotally supported end of said waveguide with said first waveguide for preventing escape of radio energy.

3. In a device for coupling energy in a -first-hollow rectangular dielectric-filled waveguide to a selected one of several adjacent hollow rectangular dielectric filled waveguides, a block mounted on each outer side wall of said first waveguide, the opposed faces of said blocks and the end of said first waveguides being curved to form substantially a semi-cylindrical surface, a second hollow rectangular dielectric-filled waveguide pivotally mounted at one end on an axis coaxial with the axis of said semi-cylindrical surface, the opposed faces of said blocks having slots formed therein extending parallel to said axis, said slots having an electrical depth substantially equivalent to a quarter wavelength of the wavelength of the electrical energy being coupled and being spaced from the adjacent side wall of said first waveguide a similar distance, said several adjacent waveguides radially disposed with respect to said axis and having their ends located in the path of the outer end of said pivotal section of waveguide so as to be successively aligned therewith as said section is pivoted.

4. A radio frequency choke for a hollow dielectric-filled waveguide comprising a pair of blocks mounted on the outsides of opposed side walls of the waveguides adjacent one end thereof, the end of said waveguide and one face of each of said blocks defining a concave segment of a cylindrical surface of revolution having an axis perpendicular to the longitudinal axis of said waveguide, said blocks -.having slots formed in said faces, said slots extending parallel to the axis of said surface of revolution and having a depth equivalent to a quarter wavelength of the frequency of transmission and being spaced from the sidewalls of said waveguide an equivalent distance.

5. A radio frequency choke for a hollow dielectricfilled waveguide comprising a pair of blocks mounted on the outsides of opposed side walls of the waveguide adjacent one end thereof, the end of said waveguide and one face of each of said blocks defining a concave segment of a cylindrical surface of revolution having an axis perpendicular to the longitudinal axis of said waveguide, said blocks having slots formed in said faces extending parallel to the axis of said surface of revolution and being spaced from the side walls of said waveguide by a distance equivalent substantially to a quarter wavelength of the frequency of transmission, the depth of said slots being electrically equivalent to substantially a quarter wavelength of the frequency of transmission, and a quantity of dielectric material filling said slots.

6. In a device for coupling energy in a first hollow rectangular dielectric-filled waveguide to a selected one of several adjacent hollow rectangular dielectric-filled waveguides, a block mounted on each side wall of said first waveguide adjacent an end thereof, the opposed faces and the end of said waveguide being curved to form a substantially semi-cylindrical surface of revolution, said blocks having slots. formed in the opposed surfaces thereof extending parallel to the axis of said surface of revolution and being spaced from the side walls by a distance equivalent substantially to a quarter wavelength of the wavelength of electrical energy being coupled, the depth of said slots being electrically equivalent to a quarter wavelength of the wavelength of the energy being coupled, a second hollow rectangular dielectric-filled waveguide pivotally mounted at one end on an axis coaxial with the axis of said surface of revolution, said several adjacent waveguides to which energy is to be coupled being radially disposed with respect to said axis and having their ends located in the path of the outer end of said pivotal waveguide so as to be successively aligned therewith as said waveguide is pivoted.

7. Means for transmitting radio frequency energy comprising a first hollow dielectric-filled waveguide and a second hollow dielectric-filled waveguide, convex means secured to one end of said second waveguide defining a convex surface, said one end of said second waveguide lying in said convex surface, concave means secured to one end of said first waveguide defining a concave surface, said one end of said first waveguide lying in said concave surface, means supporting said second waveguide for pivotal motion about said one end with said concave surface in opposed adjacent relation to said convex surface, whereby said pivotal motion will move said convex surface relative to said concave surface in a direction substantially parallel to said surfaces, said convex and concave surfaces defining a narrow dielectric space therebetween, and radio frequency impedance means in said concave surface for substantially preventing leakage of said radio frequency energy out of said waveguides through said dielectric space.

8. Means for transmitting radio frequency energy comprising a first hollow dielectric-filled waveguide and a second hollow dielectric-filled Waveguide, convex means secured to one end of said second waveguide defining a convex surface, said one end of said second Waveguide lying in said convex surface, concave means secured to one end of said first waveguide defining a concave surface, said one end of said first waveguide lying in said concave surface, means supporting said second waveguide for pivotal motion about said one end with said concave surface in opposed adjacent relation to said convex surface, whereby said pivotal motion will move said convex surface relative to said concave surface in a direction substantially parallel to said surfaces, said convex and concave surfaces defining a narrow dielec- Iric space therebetween, and a slot-like depression in said concave surface substantially surrounding said one end of said first waveguide, said depression having a depth equivalent to a quarter wavelength of the frequency of said coupled energy and being spaced from said one end of said first waveguide an equivalent distance.

References Cited in the file of this patent UNITED STATES PATENTS 2,360,219 Goddard Oct. 10, 1944 2,400,777 Okress May 21, 1946 2,407,318 Mieher Sept. 10, 1946 2,419,613 Webber Apr. 29, 1947 2,460,401 Southworth Feb. 1, 1949 2,476,621 Okress July 19, 1949 2484,822 Gould Oct. 18, 1949 2,563,990 Cutler Aug. 14, 1951 2,573,713 Kannenberg Nov. 6, 1951 

